<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            height:200px;
            display: grid;
            grid-template-columns: 200px 1fr 200px;
        }
        .right{
            background-color: red;
        }
        .main{
            background-color: blue;
        }
        .left{
            background-color: green;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="right"></div>
        <div class="main"></div>
        <div class="left"></div>
        <div class="right"></div>
        <div class="main"></div>
        <div class="left"></div>
    </div>
</body>
</html>